Efficacy of entomopathogenic fungi, nematodes and spinetoram combinations for integrated management of Thrips tabaci.

BACKGROUND: Two consecutive field trials using a blend of entomopathogens in combination with a new chemistry insecticide were conducted to determine treatment effects on onion thrips (Thrips tabaci Lindeman) populations, crop damage, plant development, crop yield and impact on natural enemies. Products were tested in an onion cropping system and included the insect pathogenic fungus Beauveria bassiana (isolate WG-11), an entomopathogenic nematode Heterorhabditis bacteriophora (strain VS) and the new-chemistry chemical insecticide spinetoram. RESULTS: In all treatments, a significant decrease in thrips per plant population was detected in both trials. Overall, dual application of entomopathogens and insecticide was more effective than singly applied treatments. The lowest number of thrips larvae (1.96 and 3.85) and adults (0.00 and 0.00) were recorded when treated with dual application of B. bassiana and spinetoram at 7 days post application (DPA) after the second spray application in 2017and 2018, respectively. Damage on onion plants was considerably decreased in all treatments relative to the control. The lowest damage was observed on onion plants treated with B. bassiana + spinetoram at 7 DPA after the second spray application during both years. A significant decrease in the number of natural enemies (beetles, spiders, mites, lacewings, ants and bugs) on onion plants was recorded during both years. Insect pathogens when applied alone and in combination with each other considerably protected arthropod natural enemies compared to insecticide application applied alone. Significant increase in plant agronomic traits was observed compared to the control. Among all the treatments, B. bassiana + spinetoram produced maximum leaf length, leaf weight, total leaves, neck diameter, bulb diameter, number of rings per bulb, bulb weight, dry matter and plant yield following the 2017and 2018 applications, respectively. CONCLUSION: The findings of the study reveal the potential of using insect pathogens and insecticide for control of T. tabaci. However, combinations containing spinetoram are harmful to nontarget organisms, whereas biological control agents help in protecting biodiversity in onion agroecosystems. © 2023 Society of Chemical Industry.

Establishment of Beauveria bassiana as a fungal endophyte in potato plants and its virulence against potato tuber moth, Phthorimaea operculella (Lepidoptera: Gelechiidae).

The potato tuber moth, Phthorimaea operculella, is the most damaging potato pest in the world and is difficult to control as the larvae are internal feeders in the foliage and tubers. Entomopathogenic fungi that colonize plants as endophytes have lethal and sublethal pathological effects on insect pests. We show that Beauveria bassiana colonizes the aerial parts of potato plants endophytically after inoculation through soil drenching. Endophytic B. bassiana persisted in potato foliage for more than 50 days postinoculation. Bioassays indicated that foliage of B. bassiana-inoculated potato plants were pathogenic against larvae of P. operculella. Sublethal experiments indicated that B. bassiana negatively affected the growth, development, and reproduction of P. operculella. Development experiments showed that the weight of P. operculella pupae reared on B. bassiana-colonized potato plants (4.25 mg) was significantly less than that of those reared on uninoculated control plants (8.89 mg). Compared with newly eclosed larvae fed on control plants, those fed on B. bassiana-inoculated plants had significantly lower survivorship, with only 17.8% developing to the adult stage. Oviposition of P. operculella females reared on B. bassiana endophytically colonized plants was significantly lower (35 eggs/female) than of those reared on uninoculated plants (115 eggs/female). This study demonstrates that endophytic B. bassiana can be a potential biological control agent for the control and management of P. operculella. Comparing pupal weights of P. operculella reared on potato plants inoculated with the B. bassiana strain GZGY-1-3 and on untreated control plants, pupae from the control plants were significantly heavier than those from treated plants.

The association of extracts of Achyrocline satureioides and the fungus Beauveria bassiana against the tick Rhipicephalus microplus.

The tick Rhipicephalus microplus (Canestrini) is a major economic hurdle to the global livestock industry. The incorrect and indiscriminate control carried out by synthetic chemical compounds has contributed to the emergence of parasite resistance present today to many products available in the veterinary market. Effective, economically viable and potentially safe alternatives need to be investigated, including herbal medicine and biological control by entomopathogenic fungi. In this study, extracts from Achyrocline satureioides (Lam.) DC. obtained by extraction with solvents of different polarities associated and not associated with the entomopathogenic fungus Beauveria bassiana (Balsamo-Crivelli) Vuillemin were evaluated on different stages of the life cycle of R. microplus. The activity of plant extracts, fungus and their associations in ticks was analyzed in vitro through the adult immersion test, larval packet test and larval immersion test. The highest efficacy on engorged females (43.3%) was reached by the hexanic partition (ASh) at 5 mg/mL + fungus, reducing larval hatchability. ASh associated with B. bassiana also caused high mortality of larvae, reaching LC50 of 6.23 and 2.65 mg/mL in the packet and immersion tests, respectively. The results obtained showed that extracts, when used in combination with the fungus, have their action enhanced, reaching 100% mortality of larvae. Among the evaluated methodologies, it was observed that the larval immersion test allows better assessment, due to the time of contact with the larvae. The results obtained with A. satureioides associated with the fungus are considered promising and open new perspectives for future product development.

Control of Fusarium and nematodes by entomopathogenic fungi for organic production of Zingiber officinale.

Ginger (genus Zingiber) is widely used as a spice and a medicinal herb worldwide and is the major ingredient of traditional local drinks such as jamu in Southeast Asia. Because ginger is frequently consumed, there is an increasing interest in organic ginger production without the use of synthetic agrochemicals. Recent studies have reported that certain kinds of entomopathogenic fungi (EPF) can establish endophytic- or mycorrhiza-like relationships with plants, thereby promoting plant growth and health, in addition to their typical role in crop protection as biological control agents. In this study, we explored the possibility of non-entomopathogenic effects of EPF Beauveria bassiana and Cordyceps fumosorosea on ginger plants (Zingiber officinale) via antagonism with Fusarium oxysporum or the parasitic nematode Meloidogyne incognita. The two EPF negatively affected the growth of F. oxysporum and survival of M. incognita in vitro. The application of EPF did not have any negative effect on the growth of ginger plants. Soil chemical properties were not different between the plots with or without EPF application, while the diversity of soil bacteria was observed to increase on application of EPF. At least C. fumosorosea appeared to persist in soil during the period of ginger cultivation. Thus, these EPF are potentially useful tools for producing chemical-free ginger.

Mechanism of Action of Endophytic Fungi Hypocrea lixii and Beauveria bassiana in Phaseolus vulgaris as Biopesticides against Pea Leafminer and Fall Armyworm.

Endophytic fungal isolates Hypocrea lixii F3ST1 and Beauveria bassiana G1LU3 were evaluated for their potential to endophytically colonize and induce active compounds in Phaseolus vulgaris, as a defense mechanism against pea leafminer (Liriomyza huidobrensis) and fall armyworm (Spodoptera frugiperda). Endophytic colonization was achieved through seed inoculation with the volatile emissions from P. vulgaris plants being analyzed using GC-MS. The crude extracts of P. vulgaris obtained using methanol and dichloromethane were assayed against leafminer and fall armyworm larvae using leaf dipping and topical application, respectively. The two isolates successfully colonized the entire host plant (roots, stems, and leaves) with significant variation (p < 0.001) between fungal isolates and the controls. The results showed qualitative differences in the volatile profiles between the control plants, endophytically colonized and insect-damaged plants attributed to fungal inoculation and leafminer damage. The crude methanol extracts significantly reduced the percentage pupation of 2nd instar leafminer larvae (p < 0.001) and adult-flies emergence (p < 0.05). The survival of the 1st instar fall armyworm larvae was also significantly reduced (p < 0.001) compared to the controls. This study demonstrated the high potential of endophytic fungi H. lixii and B. bassiana in inducing mainly specific defense compounds in the common bean P. vulgaris that can be used against pea leafminer and fall armyworm.

Evaluating the Endophytic Activities of Beauveria bassiana on the Physiology, Growth, and Antioxidant Activities of Extracts of Lettuce (Lactuca sativa L.).

Endophytic entomopathogens have growth promoting, nutrient fortifying, and anti-insect properties that could improve the yield and quality of lettuce (Lactuca sativa L.). Lactuca sativa is a vegetable crop with high demand; however, it is susceptible to aphid infestations. This study's objectives were to assess the pathogenicity of Beauveria bassiana (strain: SM3) (Bals.) Vuil. (Hypocreales) against Myzus persicae Sulzer, tissue colonization of lettuce by conidia of B. bassiana, as well as the effects of fungal inoculation on growth, tissue nutrient content, and proximate composition of the lettuce plants. Furthermore, the involvement of tissue nutrients in mediating the influence of endophytic fungus on the plant traits was examined. Insects and plants were exposed to four fungal conidial concentrations: 0, 1 × 106, 1 × 107 and 1 × 108 conidia mL-1 in an anti-insect bioassay and a greenhouse experiment, respectively. The B. bassiana strain was pathogenic against M. persicae, inducing mean insect mortality of 78% at the highest concentration (1 × 108 conidia mL-1). The B. bassiana endophytically colonized up to 76% of plants exposed to 1 × 108 conidia mL-1. Crown size and plant height varied significantly among treatments. However, the plant fresh and dry weights and nutrient elements N, P, K, Ca, and Mg did not vary significantly among treatments. Among the plant macronutrients assessed, only tissue carbon content was significantly (p < 0.01) affected by conidial treatments. The tissue C and Cu contents significantly correlated with the antioxidant capacity of the lettuce plants. Most of the micronutrients, viz. Mn, Fe, Cu, and B were remarkably higher (p < 0.05) in the fungus-treated plants than in the control plants. The antioxidant capacity (FRAP and TEAC) of plant extracts varied significantly (p < 0.001) among treatments, with the highest conidial treatment yielding the most increased antioxidant activity. In conclusion, the B. bassiana strain was endophytic to lettuce, pathogenic against M. persicae, and induced increased micro-nutrient tissue contents and antioxidant activities. This study demonstrated that B. bassiana could be potentially used in the biofortification of nutritive and medicinal qualities of plants.

Biological control of Western flower thrips, Frankliniella occidentalis using a self-sustaining granular fungal treatment.

Western flower thrips (WFT), Frankliniella occidentalis, is one of the most destructive pests of vegetables, fruits and ornamental crops worldwide, causing extensive damage by direct feeding of the crop and transmitting economically important viruses. Despite the successes of biocontrol agents to control WFT, more efficient and cost-effective ways must be found to encourage grower adoption of integrated pest management. A sustainable fungal treatment was developed to preserve fungal inoculum in potting soil and reduce thrips populations. Combining cooked, oven-dried millet with BotaniGard® (a commercial form of Beauveria bassiana strain GHA) to potting soil increased spore production and persistence of the fungus in the soil. In treated pots with millet, spore concentrations were 3-4 times greater after 30 days compared with spore yields at 10 days. The number of WFT adults was significantly lower in the marigold pots treated with GHA mix + millet than untreated controls, 12% and 10% in treated pots and 70% and 68% in untreated pots in sterile and non-sterile soil, respectively. Incorporation of millet in the potting mix enhanced the effect of the fungal treatments by providing a nutritive substrate on which the fungus could become established. This method is relatively inexpensive and easy for growers to use in greenhouses because granular formulations of B. bassiana are not commercially available.

Isolate-Specific Effect of Entomopathogenic Endophytic Fungi on Population Growth of Two-Spotted Spider Mite (Tetranychus urticae Koch) and Levels of Steroidal Glycoalkaloids in Tomato.

Entomopathogenic fungi (EPF) can be experimentally established in several plant species as endophytes. Ecological effects of EPF inoculations on plant growth and plant-herbivore interactions have been demonstrated, potentially by altering plant physiological responses. However, the role of these responses in plant-fungus-herbivore tripartite interactions has not been well elucidated. Steroidal glycoalkaloids (SGAs) are plant specialized metabolites with bioactive properties against arthropod herbivores. Here, the effects of seed treatments by three EPF isolates, representing Beauveria bassiana, Metarhizium brunneum, and M. robertsii, on population growth of two-spotted spider mites (Tetranychus urticae Koch) were evaluated on tomato (Solanum lycopersicum). The levels of two SGAs, α-tomatine and dehydrotomatine, were determined in tomato leaves by LC-MS with and without T. urticae infestations after EPF inoculations. Interestingly, the population growth of T. urticae was significantly highest with M. brunneum and lowest with M. robertsii and B. bassiana at 15 days after infestation. Overall there was a significant negative correlation between SGAs content and the number of T. urticae. The levels of SGAs were significantly induced by T. urticae presence in all treatments, while only M. robertsii showed significantly higher levels of SGAs than M. brunneum and control in one of two experiments. Contrastingly, the effects on SGAs accumulation and population growth of T. urticae did not directly correlate with EPF endophytic colonization patterns of the inoculated plants. This study suggests a link between ecological effects and physiological responses mediated by EPF inoculations and T. urticae infestation with potential implications for plant protection.

Enhanced (R)-2-(4-Hydroxyphenoxy)Propionic Acid Production by Beauveria bassiana: Optimization of Culture Medium and H2O2 Supplement Under Static Cultivation.

(R)-2-(4-hydroxyphenoxy)propionic acid (HPOPA) is a key intermediate for the preparation of aryloxyphenoxypropionic acid herbicides (R-isomer). In order to improve the HPOPA production from the substrate (R)-2-phenoxypropionic acid (POPA) with Beauveria bassiana CCN-A7, static cultivation and H2O2 addition were attempted and found to be conducive to the task at hand. This is the first report on HPOPA production under static cultivation and reactive oxygen species (ROS) induction. On this premise, the cultivation conditions and fermentation medium compositions were optimized. As a result, the optimal carbon source, organic nitrogen source, and inorganic nitrogen source were determined to be glucose, peptone, and ammonium sulfate, respectively. The optimal inoculum size and fermentation temperature were 13.3% and 28°C, respectively. The significant factors including glucose, peptone, and H2O2, identified based on Plackett-Burman design, were further optimized through Central Composite Design (CCD). The optimal concentrations/amounts were as follows: glucose 38.81 g/l, peptone 7.28 g/l, and H2O2 1.08 ml/100 ml. Under the optimized conditions, HPOPA titer was improved from 9.60 g/l to 19.53 g/l, representing an increase of 2.03- fold. The results obtained in this work will provide novel strategies for improving the biosynthesis of hydroxy aromatics.

Revealing mitogenome-wide DNA methylation and RNA editing of three Ascomycotina fungi using SMRT sequencing.

Beauveria bassiana, Cordyceps militaris and Ophiocordyceps sinensis (Ascomycotina) are traditional Chinese medicines. Here, mitogenomes of these three Ascomycotina fungi were sequenced and de-novo assembled using single-molecule real-time sequencing. The results showed that their complete mitogenomes were 31,258, 31,854 and 157,584 bp, respectively, with sequencing depth approximately 278,760×, 326,283× and 69,385×. Types of repeat sequences were mainly (AA)n, (AAT)n, (TA)n and (TATT)n. DNA methylation motifs were revealed in DNA modifications of these three fungi. We discovered new models of RNA editing through analysis of transcriptomes from B. bassiana and C. militaris. These data lay a solid foundation for further genetic and biological studies about these three fungi, especially for elucidating the mitogenome evolution and exploring the regulatory mechanism of adapting environment.

Production of Omegas-6 and 9 from the Hydrolysis of Açaí and Buriti Oils by Lipase Immobilized on a Hydrophobic Support.

This paper describes a bioprocess to obtain omegas-6 and 9 from the hydrolysis of Açaí (Euterpe oleracea Martius) and Buriti (Mauritia flexuosa) oils by lipases immobilized on octyl-sepharose. For this, oils and butters were initially selected as the carbon source which resulted in higher production of lipases in Beauveria bassiana and Fusarium oxysporum cultures. The carbon source that provided secretion of lipase by B. bassiana was Açaí oil, and for F. oxysporum, Bacuri butter. Lipases obtained under these conditions were immobilized on octyl-sepharose, and both, the derivatives and the crude extracts were biochemically characterized. It was observed that the immobilization promoted an increase of stability in B. bassiana and F. oxysporum lipase activities at the given temperatures and pH. In addition, the immobilization promoted hyperactivation of B. bassiana and F. oxysporum lipase activities being 23.5 and 11.0 higher than free enzyme, respectively. The hydrolysis of Açaí and Buriti oils by the derivatives was done in a biphasic (organic/aqueous) system, and the products were quantified in RP-HPLC. The results showed the potential of these immobilized lipases to obtain omegas-6 and 9 from Brazilian natural oils. This work may improve the enzymatic methodologies for obtaining foods and drugs enriched with fatty acids.

Toxicity of Beauveria bassiana-28 Mycelial Extracts on Larvae of Culex quinquefasciatus Mosquito (Diptera: Culicidae).

Microbial-based pest control is an attractive alternative to chemical insecticides. The present study sought to evaluate the toxicity of the entomopathogenic fungus Beauveria bassiana-28 ethyl acetate extracts on different larval stages and pupae of Culex quinquefasciatus mosquitoes. B. bassiana-28 ethyl acetate mycelial extracts produced mosquitocidal activity against larvae and pupae which was comparable to that of the commercial insecticide B. bassiana-22 extract. The LC50 (lethal concentration that kills 50% of the exposed larvae) values of B. bassiana-28 extracts for 1st to 4th instar larvae and pupae were 11.538, 6.953, 5.841, 3.581 and 9.041 mg/L respectively. Our results show that B. bassiana-28 ethyl acetate mycelial extract has strong insecticidal activity against larval and pupal stages of Cx. quinquefasciatus. Fourier transform infrared spectrum study of B. bassiana-28 extract shows peaks at 3226.91; 2927.94; 1593.13; 1404.18; 1224.18; 1247.94; 1078.21; 1018.41; 229.69; and 871.82 cm-1. Major spectral peaks were observed at 3226.91 cm-1, assigned to N-H stretching, 2927.94 cm-1 assigned to C-H bonding and 1595.13 cm-1 assigned to C-O stretching. Gas Chromatography-Mass Spectrometry studies of B. bassiana-28 ethyl acetate crude extract showed presence of six major compounds viz. N-hexadecanoic acids (13.6040%); Z,Z-9,12 octadecadienic acid (33.74%); 9-eicosyne (10.832%); heptacosane (5.148%); tetrateracontane (5.801%); and 7 hexyleicosane (5.723%). Histology of mosquito midgut tissue shows tissue lysis as a result of B.bassiana-28 extract exposure. The study shows that bioactive molecules obtained from B. bassiana-28 mycelial extract has insecticidal properties and can be used as alternative for mosquito control.

Microscopic investigation to determine the effect of Beauveria bassiana (Bals.) Vuill. and Cymbopogon citratus (DC.) Stapf. treatment on different life stages of Musca domestica (L.).

Microscopic investigation was done to determine the effect of entomopathogenic fungi, Beauveria bassiana and essential oil of Cymbopogon citratus on different life stages of Musca domestica. Scanning electron microscopy investigation of fungal infected larvae showed sluggish movement, rigor, and failure of body to balance in water. Treated larvae also revealed varied level of cuticle shrinkage and extreme dehydration. Surface of B. bassiana infected pupae showed varied stage of mycelial growth, while the cadaver of adult fly was observed to have extensive fungal growth covering their entire body surface. The application of C. citratus oils on M. domestica larvae resulted in skin shrinkage, spinous cells proliferation and bleb formation, while the treated pupae showed high incidence of incomplete emergence and malformation in emerged adult flies. The current study establishes effect of C. citratus essential oil and B. bassiana infection on different life stages of M. domestica.

Essential oils and Beauveria bassiana against Dermanyssus gallinae (Acari: Dermanyssidae): Towards new natural acaricides.

Essential oils (EOs) and entomopathogenic fungi such as Beauveria bassiana (Bb) strains have the potential to be used as alternative insecticides and acaricides for controlling ectoparasites as Dermanyssus gallinae. These compounds have some limitations in their use: the acaricidal effect of EOs is rapid, but short-lived, whilst that of Bb is delayed, but long-lived. To evaluate the effect of both compounds combined against D. gallinae, the non-toxic dose of Eucalyptus globulus, Eucalyptus citriodora, Thymus vulgaris and Eugenia caryophyllata essential oils were firstly calculated for "native" strains of Bb. Subsequently, the effects of the combination of selected EOs with Bb against nymph and adult poultry red mites (PRMs) was assessed. EO concentrations ranging from 0.0015 to 8% v/v (i.e., nine double dilutions) were used to evaluate their effect on germination, sporulation and vegetative growth rates of native strains of Bb. A total of 1440 mites (720 nymphs and 720 adults) were divided into three-treated group (TGs) and one control group (CG). In TGs, mites were exposed to Bb in combination with the selected EO (TG1), EO alone (TG2) or Bb (TG3) alone. In the CG, mites were exposed to 0.1% tween 80 plus EO solvent (CG). E. globulus and E. citriodora were toxic for Bb in concentrations higher than 0.2% and 0.003% respectively, whilst E. caryophyllata and T. vulgaris were toxic at all concentrations tested against Bb. Based on the results of the toxicity assays against Bb, E. globulus was chosen to be tested as acaricide resulting non-toxic for Bb at concentration lower than 0.4%. Increased mortality of D. gallinae adults was recorded in TG1 than those in other TGs from 4days post-infection (T+4DPI). A 100% mortality of D. gallinae was recorded in adults at T+9DPI and at T+10DPI in nymphs in TG1 and later than T+11DPI in the other TGs. Used in combination with E. globulus, Bb displayed an earlier acaricidal effect towards both haematophagous D. gallinae stages. The combination of B. bassiana and E. globulus at 0.2% might be used for controlling arthropods of medical and veterinary importance as D. gallinae.

A Distinctive Pattern of Beauveria bassiana-biotransformed Ginsenoside Products Triggers Mitochondria/FasL-mediated Apoptosis in Colon Cancer Cells.

Ginseng is one of the most commonly used adaptogens. Transformation into the minor ginsenosides produces compounds with more effective action. Beauveria bassiana, a teleomorph of Cordyceps bassiana, is a highly efficient producer of mammalian steroids and produces large amounts of sugar-utilizing enzymes. However, the fermentation of steroid glycosides in ginseng with B. bassiana has never been studied. Thus, we evaluated the bioconversion of the major ginsenosides in white ginseng by B. bassiana. Interestingly, B. bassiana increased the total amount of protopanaxadiols and hydrolyzed Rb1 into minor ginsenosides, exhibiting high levels of Rd and Rg3, as well as moderate levels of Rb2 and Rc analyzed by high-performance liquid chromatography coupled with evaporative light-scattering detection. The ß-glucosidase activity was highly increased, which led to the selective elimination of sugar moiety at the 20-C position of Rb1 to Rd, followed by Rg3. Rb2 and Rc accumulated because of the minimal activities of α-L-arabinopyranosidase and α-L-arabinofuranosidase, respectively. The fermentation product exerted dose-dependent cytotoxicity in HCT-15 cells, which are resistant to ginseng. The product, but not white ginseng, exhibited apoptotic effects via the Fas ligand and caspase 8/9. This study demonstrates for the first time that the B. bassiana-fermented metabolites have potent apoptotic activity in colon cancer cells, linking to a therapeutic use.

Successful treatment of Beauveria bassiana fungal keratitis with topical voriconazole.

We describe a 66-year-old woman who suffered from fungal keratitis after corneal transplantation. The causative organism was identified as Beauveria bassiana on the basis of morphological characteristics and the sequence of the internal transcribed spacer region of the ribosomal RNA gene. The patient was successfully treated with topical voriconazole (VRCZ) use only. We, hereby, present the first report of a case with B. bassiana fungal keratitis that responded to topical antifungal VRCZ treatment.

Antiangiogenic-Like Properties of Fermented Extracts of Ayurvedic Medicinal Plants.

The three ayurvedic medicinal plants, Withania somnifera, Emblica officinalis, and Bacopa monnieri, were extracted by high-pressure static extraction using the Zippertex(®) technology. The extracts were mixed to reach quantifiable amounts of active compounds identified by high-pressure liquid chromatography-mass spectrometry (HPLC-MS) analysis. The mixture of extracts was incubated with resting cells of the fungus Beauveria bassiana ATCC 7159. The fermentation promoted the fluidization of the starting dense mixture, while HPLC monitoring evidenced the disappearance of glucogallin from E. officinalis extract and the concomitant increase in gallic acid content. Topical exposure of the chick embryo chorioallantoic membrane (CAM) to the nonfermented extract led to the extensive necrosis and destruction of the treated membrane. However, the fermented extract was shown to be free of any toxicity. Furthermore, compared with the untreated CAM, the fermented sample reduced CAM vascularization, suggesting its antiangiogenic potency. The innocuity of the fermented extract was demonstrated using the in vivo LD50 test, the morphological examination of internal organs of treated rats, as well as the evaluation of blood biomarkers of liver damage (aspartate aminotransferase and alanine aminotransferase). The fermented extract was developed as a nutraceutical antiangiogenic treatment of age-related macular degeneration and commercialized in an oral form named Ethnodyne-Visio™.

Biological Control of Aphid Using Fungal Culture and Culture Filtrates of Beauveria bassiana

Aphids are one of the most destructive pests in crop production such as pepper, cucumber, and eggplants. The importance of entomopathogenic fungi as alternative pest control agents is increasing. Conidia of entomopathogenic fungi are influenced by environmental conditions, such as temperature and relative humidity, and cause slow and fluctuating mortality. These factors have prevented wider application and use of biocontrol agents. For investigation of means of mitigation of such problems, we conducted bioassays with 47 fungal culture filtrates in order to evaluate the potential of secondary metabolites produced by entomopathogenic fungi for use in aphid control. Among 47 culture filtrates cultured potato dextrose broth, filtrate of Beauveria bassiana Bb08 showed the highest mortality (78%) against green peach aphid three days after treatments. Filtrate of Bb08 cultured in Adamek's medium showed higher toxicity as 100% to third instar nymphs of the aphid compared with seven other filtrates cultured in different broths amended with colloidal chitin or oil. The culture filtrates and fungal cultures from media amended with colloidal chitin or oil had lower control efficacies than filtrates without these additives in three different media. These results indicate that the fungal culture fluid or culture filtrate of B. bassiana Bb08 cultured in Adamek's medium has potential for development as a mycopesticide for aphid control.

Production of Blastospore of Entomopathogenic Beauveria bassiana in a Submerged Batch Culture

The principal objective of this study was to determine the optimal liquid culture conditions in shake flasks for maximal sporulation of Beauveria bassiana. The optimal initial pH for the spore production of B. bassiana using Potato Dextrose Broth was 5.2. The screening in shake flasks of carbon and nitrogen sources resulted in the identification of an optimal medium based on 3% sucrose and 1% casamino acid, with a C : N ratio of 22 : 4. Using this medium, a production level of 5.65 x 107 spores per ml was obtained after 5 days of culture. Using 3% corn meal, 2% corn steep powder, and 2% rice bran, the maximum spore concentration of 8.54 x 108/ml was achieved 8 days after inoculation at 25degrees C in a rotary shaking incubator operated at 200 rpm. This represents a yield gain of approximately 2.89 times that of pre-optimization.